1. Field of the Invention
The present invention relates to an adapter for holding a centrifuge tube in a centrifuge rotor cavity, and in particular, to an adapter in which a secondary seal is disposed between the pieces and in which the pieces are held by a bail.
2. Description of the Prior Art
U.S. Pat. No. 3,998,383 (Romanauskas et al.) and U.S. Pat. No. 4,015,775 (Rohde), both assigned to the assignee of the present invention, disclose centrifuge rotors of the vertical angle type. U.S. Pat. No. 5,024,646 (Lewis et al.) discloses a centrifuge rotor having tube cavities that are nearly vertical, i.e., having an angle of approximately ten degrees or less with respect to the axis of rotation.
In such rotors the axis of the rotor cavities is substantially parallel to the axis of rotation. When using a vertical angle or near-vertical angle rotor it is necessary that a cap be provided at the mouth of each cavity to impose a vertical restraining force on the tube disposed in the cavity. Even though the tube may be disposed in an adapter received within the cavity, without such a capping arrangement the possibility exists that the pressure of the liquid during centrifugation may rupture the tube. U.S. Pat. No. 3,998,383 (Romanauskas et al.) exemplifies a typical capping arrangement for a vertical angle rotor.
Such capping arrangements must be individually threaded into the rotor body. As a result such capping assemblies present, at a minimum, a tortuous path for preventing the escape of aerosols formed in the event of tube rupture. In this regard, such capping assemblies are advantageous in that they satisfy the increasing demand to provide secondary sealing for sealed tubes or containers having biohazardous materials. However, in order to provide proper support, it is necessary that the capping arrangement be in intimate contact with the tube. Improper assembly can thus lead to the possibility of tube rupture and/or cap failure. For these reasons such capping arrangements have an associated disadvantage.
Recently, however, due primarily to the hazardous nature of many of the materials being processed, the demand has increased to provide a secondary seal for the sample carried within a container tube within the rotor.
In view of the foregoing it is believed advantageous to provide an adapter for use in a vertical or near vertical angle rotor that eliminates the necessity of a capping mechanism for the rotor cavity and simultaneously affords a secondary seal to prevent the escape of biohazardous materials.
A sealed centrifuge tube adapted for use in rotors is sold by E. I. Du Pont de Nemours & Co. as the "ULTRACRIMP".TM. tube. The sealing assembly for this tube is disclosed in U.S. Pat. No. 4,552,278 (Romanauskas), assigned to the assignee of the present invention. Other sealed centrifuge tubes are disclosed in U.S. Pat. No. 4,301,963 (Nielsen), heat sealable in the manner disclosed in U.S. Pat. No. 4,291,964 (Ishimaru), and those manufactured and sold by Nalgene Inc. as the "UltraLok" tube sold by Fisher Scientific Incorporated.
U.S. Pat. No. 4,306,676 (Edwards et al.) discloses a two-piece adapter for supporting multiple open-mouthed tubes at a predetermined angle with respect to the axis of rotation in a vertical rotor cavity. A gasket is disposed between the conjoined pieces of the adapter. The pieces of the adapter are held together by a bail whose major axis extends perpendicular to the major axis of the adapter. Owing to the manner in which the bail is mounted, such an adapter would appear incapable of resisting a vertical force.
U.S. Pat. No. 3,674,197 (Mitchell et al.), assigned to the assignee hereof, the above-mentioned Nalgene Ultra-Lok Tube System, and U.S. Pat. No. 4,692,137 (Anthony) each also disclose an adapter arrangement formed of two discrete adapter segments.